and todd humphreys, the university of texas researcher behind these projects joins us now. also with us is milton clary. he works with federal government agencies to identify such threats. he's a senior analyst at overlook systems technologies. so todd humphries, this has a kind of innocuous funny even name of spoofing but it sounds rather serious. you're, in essence -- you're tricking the g.p.s. system? >> that's right. we convincingly faked the g.p.s. signals and make a receiver think it's at some other place or some other time. >> brown: why do it? what's behind this experimenting? >> well, you know, we had done experiments in our laboratory and we'd convinced ourselves that we could hack a g.p.s. receiver, make it believe it's some other place, but what does this mean? what does it entail? could you, for example, remotely and clandestinely lead an expensive and enormous ship at sea off course without the crew even knowing? that was the question we sought to answer and it turns out the answer is yes. >> brown: how do you view this spoofing? how do you think about it? >>